No single, conventional treatment has been shown to significantly benefit adults with AN, which ranks among the leading causes of disability and premature death in young women. The investigators propose to test the hypothesis that a novel, couple-based intervention developed for adult AN (UCAN) significantly enhances treatment outcome and reduces risk of relapse compared with treatment conducted entirely on an individual basis, the standard mode of treatment delivery in the community. The investigators plan to compare UCAN with individual treatment in a randomized controlled trial (RCT). All participants with AN will receive a common set of core interventions, including medical management, nutrition counseling, and a base level of individual cognitive-behavioral therapy (CBT), with randomization either to: 1) UCAN couple-based intervention or 2) a higher "dose" of individual CBT. The partners are involved in varying ways and to varying degrees in treatment. In addition, progress will be followed for one year after completion of active treatment.